Magnetoresistive device and method for manufacturing same

Abstract

The heat resistance of a magnetic resistance device utilizing the TMR effect is improved. Also, the Neel effect of the magnetic resistance device utilizing the TMR effect is restrained. The magnetic resistance device includes a first ferromagnetic layer formed of ferromagnetic material, a non-magnetic insulative tunnel barrier layer coupled to the first ferromagnetic layer, a second ferromagnetic layer formed of ferromagnetic material and coupled to the tunnel barrier layer, and an anti-ferromagnetic layer formed of anti-ferromagnetic material. The second ferromagnetic layer is provided between the tunnel barrier layer and the anti-ferromagnetic layer. A perpendicular line from an optional position of the surface of the second ferromagnetic layer passes through at least two of the crystal grains of the second ferromagnetic layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a magnetic resistance device, and more particularly, the present invention relates to a magnetic resistance device with heat resistance improved. BACKGROUND ART [0002] A development is carried forward to apply a magnetic resistance device showing a tunnel magnetic resistance effect (TMR effect) to a magnetic random access memory (MRAM) and a reproduction magnetic head of a high density magnetic recording apparatus. The TMR effect is a kind of magneto-resistance effect. As the magneto-resistance effect, a giant magnetic resistance effect (GMR effect) is known in addition to the TMR effect. However, the TMR effect which shows the magneto-resistance effect larger than the giant magnetic resistance effect (GMR effect) is preferable in application to MRAM and the reproduction magnetic head. [0003] As shown in FIG. 1, the magnetic resistance device showing the TMR effect is typically composed of an anti-ferromagnetic layer 101, a pin...

AI Technical Summary

Benefits of technology

[0015] Another object of the present invention is to restrain the Neel effect of a magnetic resistance device utilizing the TMR effect and to make a reverse magnetic field necessary to reverse spontaneous magnetization symmetrical.

[0028] The method of manufacturing a magnetic resistance device of the present invention includes (G) forming an anti-ferromagnetic layer on a surface of a substrate; (H) forming a pinned ferromagnetic layer on the anti-ferromagnetic layer in an atmosphere containing an oxidizing gas; (I) forming a tunnel barrier layer on the pinned ferromagnetic layer; and (J) forming a free ferromagnetic layer on the tunnel barrier layer. A partial pressure of the oxidizing gas during the (H) process is determined such that the first ferromagnetic layer indicates electric conductivity. By forming the pinned ferromagnetic layer on the anti-ferromagnetic layer in the atmosphere containing an oxidizing gas, the growth of crystal grains in the pinned ferromagnetic layer is obstructed and the crystal grains in the pinned ferromagnetic layer are made small. Through the miniaturization of the crystal grains in the pinned ferromagnetic layer, it is avoided that the grain boundaries of the pinned ferromagnetic layer straightly passes through the pinned ferromagnetic layer and the diffusion of the material of the anti-ferromagnetic layer to the tunnel barrier layer is restrained.

Problems solved by technology

A problem of the magnetic resistance device utilizing the TMR effect is heat resistance.

Another problem of the magnetic resistance device utilizing the TMR effect is that magnetic field necessary to reverse the direction of the spontaneous magnetization of the free ferromagnetic layer 104 is asymmetry with respect to the direction to be reversed due to the Neel effect (orange peel effect).

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